Person $A$ has information partition $\{\{1,2\},\{3,4\},\{5,6\}\}$

Person $B$ has information partition $\{\{1\},\{2,3\},\{4,5\},\{6\}\}$

$w=3$ has been realized.

I'm confused about what $A$ knows that $B$ knows.

At first I thought of it as $K_aK_b(3)=K_a(\{2,3\})=\{1,2,3,4\}$, but the example I found online says $K_aK_b(3)=\{2,3,4,5\}$. why?


The situation is not described by $K_A(K_B(3))$. $A$ does not know that the draw was 3, and hence does not know that $B$ thinks it is in the set $K_B(3)$. What $A$ does know is that the draw is in set $K_A(3)$, hence $A$ thinks $B$ should have narrowed it down to $K_B(K_A(3))$.


Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.